The proposed research deals with choice behavior in animals. The long-term objective is to develop a general theory of choice behavior that will encompass quantitative relationships between choice behavior and parameters of reinforcement in several experimental paradigms such as discrete-trials situations, free-operant situations, and single- and multi-operanda situations. The general theory will deal especially with data on the effects of reinforcement parameters on the control of temporal patterns of behavior. These data suggest traditional assumptions, such as the Law of Effect, are inadequate. These data imply that temporal contiguity between response and reinforcement is not necessary for learning to be established. In order to better understand the role of temporal contiguity, behavioral research on animal short- term memory is getting underway.